The use of passive keyless entry (PKE) systems in automobiles has increased significantly recently. The PKE systems have increased the convenience of entering an automobile, especially when the vehicle operator's hands are full. They also are more secure than prior key-based security systems. A PKE system enables a driver to lock/unlock an automobile using an induction key. The induction key can sense and identify a low frequency (LF) signal transmitted by the automobile, and use an ultra high frequency (UHF) signal emitter to lock/unlock the automobile. The accuracy and stability of sensing the LF signal by the induction key is important.